Device for relative movement of two elements

ABSTRACT

A robot for movement of a moveable element ( 2 ) relative to a base element ( 1 ) comprises at least two link devices ( 4, 5, 6 ) coupled between the elements. These link devices comprise each at least two mutually articulated link units ( 7, 8; 9, 10; 11, 12 ) and power exerting arrangements ( 13, 14, 15 ) adapted to pivot the link devices for changing the relative position of the elements. A first ( 4 ) of the link devices is connected with the moveable element ( 2 ) via a hinge connection ( 16 ) so that there are, on consideration of the robot in its entirety, at least two degrees of freedom in the form of relative pivotability about two pivot axes, real or imaginary, extending at an angle relative to each other between the first link device ( 4 ) and said element ( 2 ). A further ( 5 ) of the link devices is connected to the base element ( 1 ) via a hinge connection ( 32, 33, 28 ) which on consideration of the robot in its entirety provide for freedom of movement between the further link device ( 5 ) and the base element ( 1 ) with respect to at least two degrees of freedom consisting of pivotability about two different pivot axes, real or imaginary.

FIELD OF THE INVENTION

This invention is related to a device for relative movement of twoelements, one of which forms a base element whereas a second is movablerelative to the base element, comprising at least two link devicescoupled between the elements, said link devices each comprising at leasttwo mutually articulated link units, and power exerting arrangementsadapted to cause the link devices to pivot for changing the relativeposition of the elements, a first of the link devices being connected toone of the elements via a hinge connection so that there are, onconsideration of the device in its entirety, at least two degrees offreedom between said first link device and said element in the form ofrelative pivotability about two pivot axes, real or imaginary, placed atan angle relative to each other.

The relative movement of the two elements has the purpose to positionthem mutually in a manner aimed at by means of the power exertingarrangements. More specifically, the device according to the inventionis intended to form a manipulator or robot. The moveable of the elementsis intended to carry, directly or indirectly via a carrying arrangement,a working member to execute the function aimed at.

BACKGROUND OF THE INVENTION

A robot is described in U.S. Pat. No. 4,976,582. For the positioning ofthe second element, the known robot comprises three power exertingarrangements, which comprise three power exerting members arranged in atriangular distribution on the first element. Each of the power membersis connected to the moveable second element via its own connectioncomprising a link device each comprising at least two mutuallyarticulated link units. First link units hingedly connected to the firstlink unit and to the second element respectively via connectionsproviding, on consideration of the device in its entirety, two degreesof freedom.

A disadvantage with this known type of robot is that it becomescomparatively bulky as a consequence of the triangular distributiondiscussed herein above. Furthermore, it is structurally difficult todesign the known robot with the required flexibility concerning workingarea and movement area since the first link units project in a starshaped manner from the first element.

OBJECT OF THE INVENTION

The invention primarily aims at devising routes to develop the device ofthe kind defined by way of introduction so as to eliminate or at leastreduce one or more of the disadvantages mentioned herein above, aparticular aim being to provide a great flexibility as to the design ofthe device and an optimum of working area for the device. It issecondarily aimed at to devise routes to realise, in a rational anduncomplicated manner, transmission of movements from the base element tothe moveable element.

SUMMARY OF THE INVENTION

As far as the primary aspect of the invention is concerned, the objectpresented is achieved by a further of the link devices being connectedto another of the elements via a hinge connection which, onconsideration of the device in its entirety, provide for freedom ofmovement between said further link device and said another of theelements in respect to at least two degrees of freedom consisting ofpivotability about two different pivot axes, real or imaginary.

In this way conditions are created for a more flexible working areaadaptation of the device. Furthermore, the solution defined createspossibilities to construct the device so that one of the link devicescould be connected to, in the first instance, the base element via saidhinge connection so that the movement of the link device at least inpart becomes dependent on the movement of at least one other linkdevice. This involves a difference relative to the device according tothe U.S. Pat. No. 4,976,582 where the three link devices arefunctionally independent of each other.

A number of advantageous developments of the invention are defined inthe dependent claims. These developments and advantages in connectionwith the invention are dealt with more specifically in the followingdescription.

SHORT DESCRIPTION OF THE DRAWINGS

With reference to the enclosed drawings a more close description ofembodiment examples of the invention follows here under:

In the drawings:

FIG. 1 is a perspective view of a robot according to the invention in adiagrammatical form;

FIG. 2 is a view similar to FIG. 1 but showing an alternativeembodiment;

FIG. 3 is a further variant with respect to design;

FIG. 4 is a detail view showing how, in the embodiment according to FIG.3, the device for providing pivoting of a link device may be designed;

FIG. 5 is a partially cut, diagrammatical side view illustrating that atransmission for putting a working member on the moveable element inmovement, here in rotation, may be incorporated into a link deviceextending between the two elements;

FIG. 6 is a detail view according to the section VI—VI in FIG. 5;

FIG. 7 is a section along the line VII—VII in FIG. 5;

FIG. 8 is a view of a further variant with respect to the basic designof the robot;

FIG. 9 shows a driving arrangement forming an alternative to the oneillustrated in FIG. 8;

FIG. 10 shows, in perspective, a further robot alternative;

FIG. 11 shows, in a view similar to the one in FIG. 10, a robotembodiment of a somewhat more complex nature then the one in FIG. 10;

FIG. 12 is a perspective view of a further design variant;

FIG. 13 is a perspective view of a further robot alternative;

FIG. 14 is a view illustrating another design with regard to theconnection of the link devices to the moveable element; and

FIG. 15 is a perspective view illustrating an embodiment according tothe invention having only two link devices.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In order to simplify the understanding, like reference characters havebeen used in the following in different embodiments for similar orcorresponding components but with addition of letters specific toembodiments.

The robot illustrated in FIG. 1 is intended for relative displacement oftwo elements 1, 2. The element 1 is in this example intended to form abase element, relative to which the element 2 is intended to bepositioned in space. The element 2 is intended to carry, either directlyas indicated in FIG. 1, or indirectly via a carrying arrangement, aworking member 3. Link devices generally denoted 4, 5 and 6 respectivelyare coupled between the elements 1 and 2. Each of these link devicescomprises at least two mutually articulated link units. With respect tothe link device 4, these link units are denoted 7 and 8 respectively.With respect to the link device 5, they are denoted 9 and 10respectively. Finally, with respect to the link device 6, they aredenoted 11 and 12 respectively.

Power exerting arrangements 13, 14, 15 are adapted to impart therespective link devices 4, 5, 6 pivoting movements for the purpose ofchanging the relative position between the elements 1, 2.

A first 4 of the link device is connected to the element 2 via a hingeconnection generally denoted 16 so that there are, on consideration ofthe device in its entirety, at least two degrees of freedom in the formof relative pivotability about two pivot axes, real or imaginary, placedat an angle relative to each other between said first link device 4 andthe element 2.

A further of the link devices, in the example the one denoted 5, isconnected to the element 1 via a hinge connection generally denoted 17,said hinge connection providing for, on consideration of the device inits entirety, freedom of movement between said link device 5 and theelement 1 as concerns at least two degrees of freedom consisting ofpivotability about two different pivot axes.

With respect to the first of the link devices, namely the one denoted 4,the first link unit thereof has the character of a movement arrangement.Its second link unit 8 has, as will be explained in the following, thecharacter of a more complex link arrangement. Between the movementarrangement 7 and the link arrangement 8 there is a connectionarrangement 18 interconnecting them. The movement arrangement 7 isprovided between the connection arrangement 18 and the base element 1whereas the link arrangement 8 is provided between the connectionarrangement 18 and the moveable element 2.

The link arrangement 8 comprises at least two first links 19 connectedrelative to the connection arrangement 18 and the moveable element 2 viajoints 20, 21 to be pivotable in all directions, said first linksforming, together with the connection arrangement 18 and the moveableelement 21, at least one first four-links system FS1. The movementarrangement 7 is adapted to allow relative movement between theconnection arrangement 18 and the base element 1.

The link arrangement 8 comprises at least one third link 22 connectedrelative to the connection arrangement 18 and the moveable element 2 viajoints 23, 24 to be pivotable in all directions. The joints 20, 21, 23,24 of the first and third links 19, 22 are disposed in a triangularconfiguration. This means, accordingly, that the joints of the links 19,22 at a respective end of the links may not be present on a straightline.

The third link 22, each of the first links 19, the connectionarrangement 18 and the moveable element 2 form a third four-links systemFS3.

The first links 19 are substantially equal in length. In addition, theyare substantially parallel. The first and third links 19, 22 in the linkarrangement 8 are substantially equal in length. Besides, they aresubstantially parallel.

The movement arrangement 7 is formed by a second link arrangementcomprising at least one second link 25 pivotable relative to theconnection arrangement 8 and base element 1. More specifically, the linkarrangement 7 comprises at least two second links 25, 26, which togetherwith the connection arrangement 18 and the base element 1 form a secondfour-links system FS2. The links 25, 26 are substantially equal inlength and substantially parallel. Thus, they form a parallelogram. Thisis pivotable in its own plane by means of the power exerting arrangement13. This arrangement comprises a power exerting member 27 adapted to putthe link 25 in a pivoting movement about an axis denoted 28. On pivotingof the link 25 about the axis 28, the link 26 will pivot about the axis29 and furthermore, relative pivoting of the links 25, 26 and theconnection arrangement 18 will occur via the axes 30, 31. In this casethe joints denoted 28-30 form only one degree of freedom, i.e. a purepivoting movement.

The link unit 9 of the second link device 5 is pivotably connected to alink contained in the second four-links system FS2 via a joint 33forming a pivot axis 32 with one degree of pivoting, i.e. purepivotability, relative to said link. Thus, the joint 33 will be movedtogether with the link on pivoting of said link. Although the joint 33may be provided on each of the moveable links 25, 26 and the link in thefour-links system FS2 formed by the connection arrangement 18 to bemoved on movement of the four-link system, it is illustrated in theexample that the joint 33 is arranged on the link denoted 25 and, morespecifically, between the pivot axes 28, 30 thereof. The joint 33 shouldalways be placed at a distance from the pivotable connections of thelinks 25, 26 to the base element 1 via the axes 28, 29. The pivot axis32 of the joint 33 is substantially parallel to the pivot axes in thefour-links system FS2.

Thus, the hinge connection 16 is formed by the joints 21 and 24. Theseindividual joints each provide for at least two degrees of freedom inthe form of pivotability about two different pivot axes. The joints 21and 24 could be formed by ball joints, in which case also a third degreeof freedom in the form of rotation could be present, or cardan joints.Corresponding considerations are valid with respect to the joints 20 and23.

The link device 5 comprises the first link unit 9, which will bemoveable relative to the base element 1 with two degrees of freedom,namely pivoting movements about the separated axes 28 and 32. This meansthe desirable consequence that a change in form of the four-links systemFS2 will cause the link unit 9 and, accordingly, the link device 5 toaccompany, a fact which simplifies control of the robot and increasesthe working area.

Besides, the link device 5 comprises a further link unit 10. This isconnected to the moveable element via a hinge connection 34, which onconsideration of the device in its entirety provides for freedom ofmovement between the link device 5 and the moveable element 2 withrespect to at least two degrees of freedom consisting of pivotabilityabout two different pivot axes. Also here, the hinge connection 34 maybe formed by joints 35 in the form of ball joints, cardan joints etcproviding for two or possibly three degrees of freedom. In the example,the link unit 10 is formed by two links 36, which via the joints 35 areconnected to the moveable element 2 and via joints 37 are connected tothe link unit 9. This link unit 9 is in the example formed by one singlelink, which at its end turned away from the joint 33 is connected to thelink unit 10 via a connection providing, as viewed in the assembledstate of the device, at least two degrees of freedom in the form ofpivotability about two different pivot axes, real or imaginary. Forinstance, the joints 37 could consist of ball joints or cardan joints.In case the links 36 are connected to a cross piece 38, which in itsturn is rotatably connected with one degree of freedom to the link 9,the joints 37 could consist of simple joints having a single degree offreedom involving pivotability about axes forming an angle to the axisof rotation of the cross piece 38 relative to the link 9.

The links 36 are substantially parallel and substantially equal inlength and form, accordingly, a forth four-links system FS4. From thestated it appears that the link 9 in the example will pivot in parallelwith the links 25, 26. Thereby the link devices 4 and 5 will be able tohold the moveable element 2 in one and the same orientation, i.e. inparallelism with the connection arrangement 18 in the entire workingarea.

To achieve pivoting of the link 9, a power exerting member 39 of thepower exerting arrangement 14 acts on the link 9 via a transmission 40extending from the power exerting member 39 on the base element 1 to thelink 9 in the link device 5. More specifically, the transmission 40comprises in the example a flexible traction force transmitting element41 laid about diverting members, a first 42 of which is connected to anoutput axle of the power exerting member 39 formed as a rotary means soas to be prevented from rotation relative to the output axle and asecond 43 of which is connected to the link 9 so as to be prevented fromrotation relative thereto. Thus, by driving the rotary means 39 inopposite directions, the link 9 may be pivoted in a desired directionrelative to the link 25.

The further link device 6 has in the embodiment according to FIG. 1 onlythe function to cause the second element 2 to move in Y-direction, i.e.in a direction substantially transversely to the plane of pivoting ofthe four-links system FS2.

The variant illustrated in FIG. 2 differs from the one in FIG. 1 by thelink 9 a here being adapted to be pivoted relative to the link 25 a viaa transmission 40 a, which is not based upon traction force transmittingelements of a flexible type but instead comprises two links 44articulated relative to each other, one of said links being connected tothe rotor of the rotary means 39 so as to be prevented from rotationrelative thereto whereas the second is pivotably connected to the link 9a. It is preferred, in both FIGS. 1 and 2, that the output axle of therotary means 39 a is concentric to the pivot axis 28 of the powerexerting member 13. Otherwise the link 9 a is as before pivotablyarticulated relative to the link 25 a so that the link 9 a will bemoveable relative to the base element 1 a with two degrees of freedom.

In the variant according to FIG. 3, the link 9 b of the link device 5 bis no longer moveable relative to the base element 1 b with two degreesof freedom but only with a single one as a consequence of the powerexerting member 39 b being, with a stationary portion, rigidly connectedto the base element 1 b and, with a moveable portion, rigidly connectedto the link 9 b so that the latter will move relative to the baseelement 1 b with one single degree of freedom, which in the proceedingembodiment is formed by a pivoting movement since the power exertingmember 39 b here is illustrated as a rotary means, with the rotor ofwhich the link 9 b is rigidly connected.

In the embodiment according to FIG. 1, the link unit 11 of the linkdevice 6 is moveable with one single degree of freedom in the form of apure pivoting movement relative to the base element 1 as a consequenceof the design of the power exerting arrangement 15 as a rotary meanshaving a stator connected to the base element 1 and a rotor rigidlyconnected to the link unit 11 formed as one single link. The link unit12 according to FIG. 1 has likewise the character of a single link andis with the ends thereof rigidly connected to the link 11 and to themoveable element 2 via hinge connections 45 and 46 respectively allowingat least two degrees of freedom in the form of pivoting about axesplaced at an angle relative to each other, which may be realised by thejoints 45, 46 being formed as ball joints, in which case three degreesof freedom are present as a consequence of the additional possibilitiesto rotation, or cardan joints.

In the variant according to FIG. 3, there is the difference that thelinks 11 b and 12 b are mutually connected via a hinge connection 47allowing one single degree of freedom in the form of pivoting betweenthe links. On the contrary, the link 11 b is moveable, via a hingeconnection generally denoted 48, with two degrees of freedom relative tothe base element 1 b in contrast to the preceding embodiment. Asconcerns the link 12 b, the same is, however, connected to the moveableelement 2 b via a joint 46 b which here must present three degrees offreedom, namely two degrees of freedom in the form of pivoting aboutaxes placed at an angle to each other and a further degree of freedom inthe form of rotation about the longitudinal axis of the link 12 b.

FIG. 4 illustrates more specifically in a detail view from above of thehinge connection 48 per se that the link 11 b is rigidly connected to agear wheel 49 comprised in an angular gear. The link 11 b is pivotablysupported relative to the base element 1 b about a first axis 50. Thegear wheel 49 is in engagement with a second gear wheel 51, which isconnected to a rotor of the power exerting arrangement 15 b so as to beprevented from rotation relative to said rotor, the power exertingarrangement being formed as a rotary means having a stator connected tothe base element 1 b and a rotor connected to the gear wheel 51. Saidrotor has the character of an output axle. The link 11 b is pivotablerelative to the base element 1 b about a second axis 52 extending at anangle, in particular a substantially right angle, to the first mentionedaxis 50. Said pivotability about the axis 52 is formed by a yoke 53being rotatably supported about the output axis of the rotary means 15 band this yoke 53 carries in its turn the axis, around which the link 11b is pivotable.

The embodiment according to FIGS. 3 and 4 has the advantage that whenthe moveable element 2 b is moved in the direction x by the link device5 b, the link device 6 b will accompany while being inclined as aconsequence of rotation about the axis 52. This means that the linkdevice 6 b always will have a favourable orientation for executingcontrol forces on the moveable element 2 b.

FIGS. 5-7 illustrate a link device 6 c corresponding to the one denoted6 b in FIG. 3. As in the preceding embodiment, this link devicecomprises links 11 c, 12 c. Along this link device there is provided atransmission generally designated 54 for transmitting driving powerbetween a power exerting member 55 arranged on the base element 1 c anda working member 3 c arranged on the moveable element 2 c. Morespecifically, the transmission 54 is adapted to rotate the workingmember 3 c, e.g. about its own axis. The transmission 54 comprisestraction force transmitting elements 56, 57 laid around divertingmembers 58, 59, 60 disposed at the articulated connection 47 c of thelinks 11 c and 12 c and at the ends of the links 11 c and 12 c turnedaway from the connection 47 c. The diverting member 59 on the link 11 cis drivingly connected, via an angular gear 61, to an output drive axle62 from the power exerting member 55. Around this device axle 62 thereis arranged a tubular axle 63, with which gear wheels 64 and 65respectively are rigidly connected. The gear wheel 64 is in drivingengagement with a gear wheel 66 placed on an output axle from the powerexerting member 15 c in the form of a rotary means. The gear wheel 65 isincluded in an angular gear together with a further gear wheel 67, whichis connected to the link 11 c so as to be prevented from rotationrelative thereto. When the rotary means 15 c is operated, the tubularaxle 63 will, via the gear wheels 66 and 64, rotate about the axle 62and this puts, via the gear wheel 65, the gear wheel 67 rigidlyconnected to the link 11 c in rotation about an axle 68. This axle isarranged in an attachment 69 which is rotatably supported about an axisparallel to the axle 62 and the tubular axle 63, more specifically bythe attachment 69 being rotatably supported about a portion of thetubular axle 63. This means that the link 11 c will be able to pivotrelative to the base element 1 c about the axle 68 and an axleperpendicular in relation to this axle 68 and concentric to the axle 62.Thus, there are two degrees of freedom for the link 11 c in accordancewith the preceding embodiment.

At that end of the link 12 c which is closest to the moveable element 2c, a gear wheel 70 is connected to the diverting member 60 so as to beprevented from rotation relative thereto, said gear wheel 70 beingincluded in an angular gear since it is in engagement with a furthergear wheel 71, which is rigidly connected to an axle 72, to which also afurther gear wheel 73 is connected. This gear wheel 73 is contained in afurther angular gear since it is in engagement with the gear wheel 74,which is connected to the working member 3 c so as to be prevented fromrotation relative thereto.

It appears from FIG. 7 that a yoke like attachment 75 operates as acarrier for an axle 76, around which the link 12 c is pivotable relativeto the moveable element 2 c. This attachment 75 is in its turn pivotablyarranged around an axis extending at an angle, preferably asubstantially right angle, to the axle 76, in the example the axledenoted 72 and carrying the gear wheels 71 and 73. Thus, there arebetween the link 12 c and the moveable element 2 c two degrees offreedom in the form of pivotability around double pivoting axes relativeto the moveable element 2 c, said pivoting axes extending at an angle toeach other. On operation of the rotary means 55, the axle 62 and thegear wheel 77 placed thereon and comprised in the angular gear 61 willbe put into rotation and this causes rotation of the gear wheel 78rigidly connected to the diverting member 59. Thus, this causes thetraction force transmitting element 56 to be driven around, a fact whichputs the diverting member 58 in rotation. This is in engagement with thetraction force transmitting element 57, which means that also thediverting member 60 and the gear wheel 70 rigidly connected thereto areput into rotation. This rotation is, via the angular gears 70/71 and73/74, transferred into rotation of the working member 3 c.

The embodiment according to FIGS. 5-7 has the advantage that both powermembers 55 and 15 c for pivoting the working member and pivoting thelink device 6 c may be disposed on the base element 1 c so that aminimum of mass inertia is achieved.

FIG. 8 illustrates a variant where the link device 5 d as in theembodiment according to FIG. 3 has a link 9 d, which is put into motion,by means of the power exerting member 39 d, in a movement with only onedegree of freedom, namely a pure pivoting movement. A power exertingmember 15 d serves for putting the link 11 d of the link device 6 d intoa pivoting movement about an axle 77. The movement of the link 11 drelative to the power exerting member 15 d occurs with one single degreeof freedom. However, the power exerting member 15 d is in this caseadapted to be put into a rotational movement of the power exertingmember 39 d belonging to the link device 5 d in that a base of the powerexerting member 15 d is connected to the output axle of the power member39 d. Said output axle from the power member 39 d extends substantiallyperpendicularly relative to the axis 77. Thus, the link 11 d will bemoveable relative to the base element 1 d with two degrees of freedom,i.e. pivoting movements around double pivot axes inclined relative toeach other. This means that when the link 9 d is pivoted by means of thepower member 39 d, the power member 15 d and then also the link 11 dwill accompany. The joint 45 d between the links 11 d and 12 d as wellas the joint 46 d between the link 12 d and the moveable element 2 d aredesigned to allow at least two degrees of freedom in the form ofpivoting around axes placed at an angle to each other. The embodimentaccording to FIG. 8 makes it possible to rationally provide atransmission extending along the links 11 d and 12 d to cause theworking member 3 d to rotate. This transmission may for instance bebased on use of axles and cardan joints.

FIG. 9 illustrates a variant of the embodiment according to FIG. 8.According to this variant, both of the power exerting members 15 e and39 e will be capable of being arranged on the base element 1 e so thatthe mass inertia becomes minimal. More specifically, the power exertingmember 39 e acts on the link 9 e by an output axle from the power membercomprising a gear wheel 78 in engagement with a gear wheel 79 rigidlyconnected to an axle 80, to which also the link 9 e is rigidlyconnected. The axle 80 is designed as a tubular axle and receives anaxle 81, which is in driving connection with the power exerting member15 e. A gear wheel 82 is connected to the axle 81 so as to be preventedfrom rotation relative thereto and this gear wheel 82 as well as afurther gear wheel 83 rigidly connected to the link 11 e forming anangular gear to subject the link 11 e to pivoting movement around anaxle 68 e. An attachment 84 carries the axle 68 e and is connected tothe tubular axle 80 so as to be prevented from rotation relative theretoin order to be put into a rotation about the axle 81 together with thetubular axle 80 by means of the power exerting member 39 e. As in theembodiment according to FIG. 8, link 11 e will accompany on pivoting ofthe link 9 e.

FIG. 10 illustrates a variant deviating from the one in FIG. 8 by thepower member 39 h here having a stationary portion secured to the baseelement 1 h without any direct connection to the power exerting member39 h for the link device 6 h. Instead, the power member 15 h is hererotatably supported with a base portion relative to the base element 1 habout an axle 92. A moveable portion of the power member 15 h is rigidlyconnected to the link 11 h. Accordingly, the link 11 h will be moveablerelative to the stationary portion of the power member 15 h with onesingle degree of freedom, namely pure pivoting, whereas the power member15 h will be moveable relative to the base element 1 h with a furtherdegree of freedom, namely pure pivoting, and this more specificallyabout an axis extending at an angle to the pivot axis of the link 11 hrelative to the base portion of the power member 15 h. The effect ofthis is that the link 11 h will be moveable relative to the base element1 h with two degrees of freedom. When the link device 5 h is pivotedwith assistance of the power member 39 h, the link device 6 h will beable to accompany by the base portion of the power member 15 h rotatingabout the axle 92. The interconnection between the link device 5 h and 6h in this regard occurs by means of a connection link 93, whichconnects, by means of hinge connections having at least two degrees offreedom, i.e. pivoting about axles angled relative to each other, thelink devices. For the rest, the embodiment is as previously described.

FIG. 11 illustrates a variant of the embodiment according to FIG. 10.The difference is a.o. that the four-links system FS2 has been arrangedpivotable about an axle 94 relative to the base element 1 i. Between thefour-links system FS2 and the connection arrangement 18 i there is alsorotatability about an axle 95. The axles 94, 95 are substantiallyparallel to each other. In order to maintain the orientation of theconnection arrangement 18 i relative to the base element 1 i, there isbetween the base element and the connection arrangement 18 i a furtherlink 96, which forms, with the four-links system FS2, a furtherfour-links system, which on pivoting of the four-links system FS2 willmaintain the orientation of the connection arrangement 18 i relative tothe base element 1 i. The further link 96 must be connected to the baseelement 1 i and the connection arrangement 18 i, via joints having atleast two degrees of freedom. In contrast to the preceding embodiment,the power exerting member 15 i is here arranged directly on the baseelement 1 i so that the link 11 i will describe a movement having onlyone degree of freedom relative to the base element 1 i, namely in theexample pure pivoting. In the embodiment according to FIG. 11, theindividual link 9 in the preceding embodiment has been replaced with alink unit 9 i forming a four-links system. This four-links system is, bymeans of the power member 39 i, pivotable relative to the base element 1i in a plane of pivoting orientated substantially perpendicularly toplanes, in which the four-links system 9 i is possible to change as toform. The four-links system 9 i is then connected to the link unit 10 iwhich also is designed as a four-links system. In this case there arebetween the link 11 i in the link device 6 i and the connectionarrangement 18 i and the four-links system 9 i links 97 and 98respectively, which cause the connection arrangement 18 i and thefour-links system 9 i to be able to accompany when the link 11 i ispivoted by means of the power member 15 i.

The variant according to FIG. 12 is in reality equivalent to the one inFIG. 10. However, the link 93 j is here coupled between the links 9 jand 11 j respectively whereas the power member 15 j is provided on thebase element 1 j. A moveable portion of the power member 15 j isconnected to the link 11 j to pivot the same. This moveable portiondenoted 99 is, however, rotatably coordinated with the link 11 j so thatwhen the link 9 j is pivoted by means of the power member 39 j, the link11 j will be able to accompany freely in pivoting movementssubstantially parallel to the pivot axis for the movable portion 99 butwhen the power member 15 j is activated, the moveable portion 99 thereofwill, on rotation, force the link 11 j to accompany. However, there isalso here as appears from the description, a freedom of movement betweenthe link 11 j and the base element 1 j having regard to two degrees offreedom, namely pivotability about double pivot axes angled relative toeach other.

The variant according to FIG. 13 differs mainly from the one in FIG. 11by FS2 and the further link 96 being operated in altitude by means of afurther link device 100, which operates as a power intermediary betweena power exerting member 101 and the connection arrangement 18 k. Thelink device 100 comprises a link arm 102 which is moveable with onesingle degree of freedom, in the example pure pivoting, relative to thebase element 1 k and which via four-links system 103 similar to the onepreviously denoted 10 is connected to the connection arrangement 18 k.The four-links system 103 could also engage on links forming aconnection between the base element 1 k and the connection arrangement18 k. Between the connection arrangement 18 k and the link 11 k in thelink device 6 k there is a connection 104 connecting together thepivoting movement of the link 11 k with the connection arrangement 18 kso that the later is displaced when the link 11 k is pivoted.

The variant in FIG. 14 corresponds substantially to what has beendescribed earlier with the exception that the links 191 and 221 here areconnected to sleeves 105 and 106 respectively via joints having onesingle degree of freedom, namely in the embodiment freedom to pivotabout one single axis. These sleeves 105, 106 are in their turnrotatably journalled about axles 107 and 108 respectively. The axle 108is conceived to form a constituent of the moveable member 11, at whichthe working member 31 is arranged. The moveable member 11 is rotatablyjournalled around the axle 107. The link device 61 acts on the axle 107in a manner which in principle already has been described. The purposeof the embodiment according to FIG. 14 is most closely to demonstratethat many variants are possible when it comes to realise the hingeconnection between the links and other constituents contained in therobot structures. The applications in question are, accordingly, onlyrestricted by the definitions appearing from the appendant patentclaims.

FIG. 15 illustrates a variant deviating from the one in FIG. 1 in thesense that here the link devices 5 and 6 present in FIG. 1 have beenreplaced by one single link device 5 m. This is coupled, with a firstlink unit 10 m, to the moveable element 2 m via a connection 109comprising one single degree of freedom, namely pivoting about onesingle axis. In the example it is illustrated that the link unit 10 mcomprises only one single link. It should be understood that two or morelinks may be arranged in parallel to improve stability if this would bedesired.

The link device 5 m comprises, furthermore, a link unit 9 m which isconnected to the link unit 10 m with two degrees of freedom, i.e. in theexample pivoting about double axes placed at an angle relative to eachother. Although said two degrees of freedom may be realised with cardanjoints or similar, a cross piece 38 m as in FIG. 15 may also be moveablewith one degree of freedom relative to the link 10 m, i.e. by purerotation whereas this cross piece then is connected to the two links 110comprised in the link unit 9 m via joints 111 also comprising one singledegree of freedom, i.e. pure pivotability but this about axes which areangled relative to the axis, around which the cross piece 38 ispivotable relative to the link 10 m.

The links 110 are then also connected to the base element 1 m via twodegrees of freedom. More specifically, a cross piece 112 is in theexample rotatably supported relative to the base element 1 m with onesingle degree of freedom and then the links 110 are hingedly connectedto this cross piece 112 also with one single degree of freedom, namelypure pivoting. The pivoting of the links 110 relative to the cross piece112 occurs around axles placed at an angle relative to the axis ofrotation of the cross piece 112 relative to the base element 1 m.

It should be observed that it is essential in the embodiment accordingto FIG. 15 that the parallelogram formed by the links 110 and the crosspieces 38 m and 112 is rigid to rotation, i.e. that the cross pieces 112and 38 m comprised in the parallelograms are maintained substantialparallel, the link 10 m between the moveable element 2 m and the crosspiece 38 m also being allowed to have one single degree of freedom inthe form of pure pivotability in order to achieve stabilisation of themoveable element 2 m.

Furthermore, it is pointed out that the four-links system FS2 also mustbe secured against rotation, i.e. adapted to be able to change its formin substantially one and the same plane.

In order to operate FS2, there is as before a power exerting arrangement13 m. In order to execute required control via the link device 5 m, apower exerting member 39 m is adapted to pivot the cross piece 112 andin this way pivot the links 110 relative to the base element 1 m whereasa further power exerting member 15 m is adapted to pivot the links 110relative to the cross piece 112 in planes substantially parallel to theaxis of rotation of the cross piece 112. It is illustrated in theexample that the power exerting member 39 m has a stationary portionconnected to the base element 1 m and a moveable portion connected tothe cross piece 112. The power exerting member 15 m is, in the example,illustrated as comprising a stationary portion rigidly connected to thecross piece 112 whereas a moveable portion of the power exerting memberis connected to one of the links 110. Expressed in other words, thelinks 110 may be operated in two planes substantially perpendicular toeach other by means of the power members 39 m and 15 m.

Common to all described embodiments is that a suitable control unit,particularly in the form of a computer, is adapted to control the powerexerting members of the various robot embodiments for the purpose ofcausing the second element 2 or members coupled thereto directly orindirectly to move in desired paths.

POSSIBLE MODIFICATIONS

It is evident that the invention is not only restricted to theembodiments discussed herein above. Thus, detail adaptations of theembodiments may be carried out depending on the circumstances withoutleaving the inventive concept appearing from claim 1.

What is claimed is:
 1. A device for relative movement of two elementscomprising: a first element forming a base element; a second elementmovable with respect to the first element; at least two link devicescoupled between the first and second elements, each of said link devicescomprising at least two mutually articulated link units; plural powerexerting arrangements provided to impart to the link devices pivotingmovements which change a relative position of the elements; a first ofthe link devices being connected to one element of the first and secondelements via a hinge connection so that there are, between said firstlink device and said one element, at least two degrees of freedom in theform of relative pivotability about two pivot axes forming an anglerelative to each other; wherein said first link device is movablerelative to another element of the first and second elements with onesingle degree of freedom; wherein a further link device is connected tosaid other element of the first and second elements via a hingeconnection which provides freedom of movement between said further linkdevice and said other element of the first and second elements includingat least two degrees of freedom consisting of pivotability about twodifferent pivot axes.
 2. A device according to claim 1, wherein thefirst of the link devices comprises: a link arrangement, a movementarrangement, and a connection arrangement interconnecting the linkarrangement and the movement arrangement, the movement arrangement beingprovided between the connection arrangement and one of the first andsecond elements, wherein the link arrangement is arranged between theconnection arrangement and the other element of the first and secondelements.
 3. A device according to claim 2, wherein the link arrangementcomprises at least two first links connected via joints relative to theconnection arrangement and an associated one of the first and secondelements to be pivotable in all directions, said first links forming,together with the connection arrangement and the associated elements, atleast one first four-links system, the movement arrangement beingadapted to allow relative movement between the connection arrangementand the associated elements.
 4. A device according to claim 3, whereinthe power exerting arrangements are adapted to actuate the linkarrangement and the movement arrangement so as to change a relativeposition of the first and second elements.
 5. A device according toclaim 3, wherein the link arrangement comprises at least one third linkconnected via a plurality of joints relative to the connectionarrangement and the associated one of the first and second elements tobe pivotable in all directions, wherein the plurality of joints of thefirst and third links are disposed in a triangular configuration.
 6. Adevice according to claim 5, wherein the at least one third link, eachof the first links, the connection arrangement and the associated one ofthe first and second elements form a third four-links system.
 7. Adevice according to claim 3, wherein the first links in the linkarrangement are substantially equal in length.
 8. A device according toclaim 3, wherein the first links in the link arrangement aresubstantially parallel.
 9. A device according to claim 2, wherein themovement arrangement is formed by a second link arrangement comprisingat least one second link pivotable relative to the connectionarrangement and an associated one of the first and second elements. 10.A device according to claim 9, wherein the second link arrangementcomprises at least two second links, which together with the connectionarrangement and the associated one of the first and second elements,form a second four-links system.
 11. A device according to claim 10,wherein the second links in the second link arrangement aresubstantially equal in length.
 12. A device according to claim 11,wherein the second links in the second link arrangement aresubstantially parallel.
 13. A device according to claim 3, wherein thefirst and third links in the first link arrangement are substantiallyequal in length.
 14. A device according to claim 13, wherein the firstand third links in the first link arrangement are substantiallyparallel.
 15. A device according to claim 1, wherein the further linkdevice is connected to another of the link devices by connection meansfor accompanying said another of the link devices in a movement thereofresulting from the power exerting arrangement.
 16. A device according toclaim 15, wherein the further link device is hingedly connected to amoveable part arranged in said another of the link devices.
 17. A deviceaccording to claim 16, wherein the moveable part is pivotable.
 18. Adevice according to claim 16, wherein a power exerting arrangementassociated with the further link device is adapted to cause a link unitarranged in the further link device to pivot relative to the moveablepart.
 19. A device according to claim 10, wherein the further linkdevice is pivotably connected at an end to a moveable link arranged inthe second four-links system.
 20. A device according to claim 19,wherein the further link device is pivotably connected to the link ofthe second four-links system about a pivot axis which is substantiallyparallel to a pivot axis of said link of the second four-links systemrelative to the associated one of the first and second elements.
 21. Adevice according to claim 17, wherein the further link device comprisesat least one first link pivotably connected to said link of the secondfour-links system, and at least one second link connected to the secondof the first and second elements in a pivotable manner.
 22. A deviceaccording to claim 21, wherein a power exerting arrangement pivots thefirst link in the second link device relative to the link of the secondfour-links system, said power exerting arrangement including a powerexerting member arranged on one of the first and second elements towhich the link of the second four-links system is pivotably connected.23. A device according to claim 22, wherein said power exerting memberacts on the first link of the further link device via a transmissioncomprising power transmission members extending along the link of thesecond four-links system.
 24. A device according to claim 22, whereinthe power exerting member acts on the first link of the further linkdevice via a link arm system comprising at least two articulated links.25. A device according to claim 1, wherein the further link device isconnected to both of the first and second elements via hinge connectionswhich allow relative movement with two degrees of freedom between saidfurther link device and each of the elements.
 26. A device according toclaim 25, wherein links arranged in the further link device are hingedlyconnected to each other via a hinge connection allowing one singledegree of freedom of movement in the form of pivoting between the links.27. A device according to claim 25, wherein the power exertingarrangement causes the further link device to pivot relative to thefirst and second elements comprises a power exerting member arranged onone of the first and second elements as a rotary means for transmittingdrive power which, via an angular gear comprising a gear wheel rigidlyconnected to one of the links in the second link device, transmits drivepower to said link, wherein said link is freely pivotable about an axissubstantially parallel to the axis of rotation of the rotary means. 28.A device according to claim 25, wherein a transmission for driving powertransmission between a power exerting member arranged on one of thefirst and second elements, and a working member arranged on the other ofthe first and second elements, is provided along the further linkdevice.
 29. A device according to claim 28, wherein the transmissioncomprises traction force transmitting elements arranged about divertingmembers and rotatably provided at an articulated connection of the linksof the further link device, and at an end of at least one of the linkswhich is turned away from the articulated connection, wherein adiverting member present at one of the ends, which are turned away fromeach other, of the links comprising the further link device is drivinglycoupled, via an angular gear, to one of the power exerting member and aworking member.
 30. A device according to claim 29, wherein the powerexerting member which causes one of the diverting members to rotate in arotary means for rotating having an axle on which a first gear wheel isdrivingly engaged with a second gear wheel connected to the divertingmember, said first and second gear wheels forming an angular gear,wherein a tubular axis is arranged about said axle and provided withmeans for driving, via the power exerting member arranged to pivot thesecond link device and a third gear wheel in engagement with fourth gearwheel rigidly connected to the adjacent link of the further link device,said third and fourth gear wheels forming said angular gear.
 31. Adevice according to claim 23, wherein the power transmission memberscomprise at least one flexible traction force transmitting element anddiverting members, about which the transmitting element is, arrangedwithin the power exerting member is adapted to rotate one of thediverting members, whereas a second of the diverting members is rigidlyconnected to the second link of the further link device.
 32. A deviceaccording to claim 1, wherein the further link device is connected tothe first of the first and second elements with at least three degreesof freedom of movement.
 33. A device according to claim 1, furthercomprising two further link devices, wherein these further link deviceseach comprise a moveable first link moved by another power exertingarrangement, wherein the moveable link of one of the further linkdevices is arranged to accompany the moveable first link of a remainingone of the further link devices in a movement involving one furtherdegree of freedom.
 34. A device according to claim 2, wherein themovement arrangement is connected to the base element with connectionsproviding two degrees of freedom.
 35. A device according to claim 3,wherein the at least one first four-links system is rotatably connectedto the base element about an axis substantially parallel to a pivotingplane of the at least one four-links system, wherein a further link ofthe movement arrangement connects to a further four-links systemoperating in parallel said further link controlling the connectionarrangement.
 36. A device according to claim 1, wherein the first linkunit of the further link device is connected to the base element via aconnection providing two degrees of freedom, wherein the second linkunit is connected to the moveable element via a connection having onedegree of freedom only, wherein the first and second link units areinterconnected via a connection providing two degrees of freedom.
 37. Adevice according to claim 1, further comprising an industrial rotor,wherein the second element of the first and second elements carries,directly or indirectly, at least one working member.